下列标点符号使用有错误的一项是（    ）

 我们每天扔掉的垃圾中，很多是宝贵的再生资源，因此生活中的垃圾要分类回收．下列物质中，属于可回收物的是（　　）

①纸张 ②塑料 ③玻璃 ④金属．

阅读下面两段文字，按要求回答问题。
                                                                                             乡 愁
                                                                                           小时候
                                                                                           乡愁是一枚小小的邮票
                                                                                           我在这头
                                                                                           母亲在那头
                                                                                           长大后
                                                                                          乡愁是一张窄窄的船票
                                                                                          我在这头
                                                                                          新娘在那头
                                                                                          后来啊
                                                                                          乡愁是一方矮矮的坟墓
                                                                                          我在外头
                                                                                          母亲在里头
                                                                                          而现在
                                                                                         乡愁是一湾浅浅的海峡
                                                                                         我在这头
                                                                                        大陆在那头

有以下几个结论：

①抛物线 $y=a{x}^2+bx+c$ 的开口向下；②抛物线 $y=a{x}^2+bx+c$ 的对称轴为直线 $x=-1$ ；③方程 $a{x}^2+bx+c=0$ 的根为0和2；④当y＞0时，x的取值范围是x＜0或x＞2.其中正确的是（   ）